This invention relates to the use of modified aminoalkyl substituted polydiorganosiloxane in hair care compositions such as conditioners and shampoos. More specifically, the invention relates to compositions and methods for treating hair with polydiorganosiloxane containing aminoalkyl groups modified by alkoxycarbonylalkyl substituents.
Aminoalkyl substituted polydiorganosiloxanes are well known copolymers which are typically composed of dimethylsiloxane units and aminoalkylmethylsiloxane units. For example, Starch, U.S. Pat. No. 4,563,347, Jan. 7, 1986. describes a copolymer represented by the formula ##STR1## Such copolymers are further described in the CTFA Cosmetic Ingredient Dictionary. 3rd edition, 1982, published by The Cosmetic. Toiletry and Fragrance Association. Inc. 1133 Fifteenth Street NW Washington D.C. (USA) under the nomenclature amodimethicone and trimethylsilylamodimethicone.
The use of aminoalkyl substituted polydiorganosiloxane in hair care compositions is also well known. For instance, Starch. U.S. Pat. No. 4,563,347, teaches using these copolymers in hair conditioning compositions to improve combing and feel characteristics. Similarly. Grollier et al., UK patent application Nos. 2,157,168 and 2.143.434, Oct. 23, 1985 and Feb. 13, 1985 respectively, teach using the aminoalkyl substituted polydiorganosiloxanes with other components in hair care compositions which may be formulated as a shampoo, a rinsed or non-rinsed lotion, a restructuring composition, a composition for blow drying, or a composition for permanent waving.
The aminoalkyl substituents are credited with providing the copolymers with cationic sites that make the polymer more substantive to hair than nonsubstituted polydimethylsiloxane. However, the chemical reactivity of the aminoalkyl groups may also present a problem in regard to compatibility with other common components of hair care formulations. Compatibility problems may be observed especially with anionic surfactants. Tangney et al., U.S. Pat. No. 4,507,455, Mar. 26, 1985, describe a method of modifying the chemical reactivity of aminoalkyl substituents of polydiorganosiloxane by reacting the polymer with a monocarboxylic acid anhydride to acylate the amine groups and thus convert them to amides. While acylation was effective to improve compatibility, it has also been found to reduce the substantivity of the polymer to hair so that the utility of the polymers in hair care compositions is limited. It is a purpose of the present invention to provide hair care compositions containing a conditioning silicone polymer which has the advantage of being highly substantive to hair but at the same time has a more moderate chemical reactivity with correspondingly reduced compatibility problems.
Aminoalkyl substituted silanes and polydiorganosiloxanes have been reacted with acrylate esters to provide silanes and polydiorganosiloxanes in which the amine is modified by addition of an alkoxycarbonylalkyl group to the nitrogen atom. For example, the reaction is illustrated as follows for methylacrylate addition to an aminopropyl substituent of a polydiorganosiloxane. EQU --CH.sub.2 CH.sub.2 CH.sub.2 NH.sub.2 +CH.sub.2 .dbd.CHCOOCH.sub.3 .fwdarw.--CH.sub.2 CH.sub.2 CH.sub.2 NHCH.sub.2 CH.sub.2 COOCH.sub.3
More specifically, Pike et al., U.S. Pat. No. 3,033,815, May 8, 1962, describe the reaction of methylacrylate with a silicone copolymer of 90 percent dimethylsiloxane units and 10 percent delta-aminobutylmethylsiloxane units. The resulting silicone is described as containing delta-(N-2-carbomethoxyethyl)aminobutylmethylsiloxane units. Pike et al. teach that these compounds find use as sizes for fibrous materials, particularly fibrous glass materials employed in combination with thermosetting resins and that the monomeric and polymeric compounds can also be employed as adhesives or as flocculation agents.
Similarly, Ryan, U.S. Pat. No. 3,317,577, May 2, 1967, describes the addition of methylacrylate to silanes and organosiloxanes having diaminoalkyl groups such as N-(2-aminoethyl)-3-aminopropyl groups (--CH.sub.2 CH.sub.2 CH.sub.2 NHCH.sub.2 CH.sub.2 NH.sub.2). Ryan teaches that the materials are useful as binding agents for binding pigments to glass fabric and other siliceous surfaces, that they are useful as priming agents on metallic surfaces for securing adhesion of subsequently applied resin coatings, that they are useful as binding agents in the preparation of glass fiber polyester laminates, and that fluids prepared from the polymers and copolymers are also of interest as heat exchange agents and for further reaction to modify organic materials.
Neither Pike et al. nor Ryan suggest that their modified aminoalkyl substituted polydiorganosiloxanes are useful in hair care compositions. The use of these materials in hair treating compositions is believed to be novel.